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Background: Early clearance of Mycobacterium tuberculosis is the eradication of infection before an adaptive immune response develops. We aimed to identify host factors associated with early clearance.Methods: Indonesian household contacts patients with smear-positive tuberculosis (TB) had an interferon-γ release assay (IGRA) at baseline and 14 weeks later. Early clearance was defined as a persistently negative IGRA. Contact characteristics, exposure, and disease phenotype were assessed for association with a positive IGRA at each time point.Results: Of 1347 contacts of 462 TB cases, 780 (57.9%) were IGRA positive and 490 (36.3%) were IGRA negative. After 14 weeks, 116 of 445 (26.1%) initially negative contacts were IGRA converters; 317 (71.2%) remained persistently negative. BCG vaccination reduced the risk of a positive baseline IGRA (relative risk [RR], 0.89 [95% confidence interval {CI} .83-.97]; P = .01), and strongly reduced the risk of IGRA conversion (RR, 0.56 [95% CI, .40-.77]; P < .001). BCG protection decreased with increasing exposure (P = .05) and increasing age (P = .004). Risk of IGRA conversion was positively associated with hemoglobin concentration (P = .04).Conclusions: A quarter of household TB case contacts were early clearers. Protection against M. tuberculosis infection was strongly associated with BCG vaccination. Lower protection from BCG with increasing M. tuberculosis exposure and age can inform vaccine development. [ABSTRACT FROM AUTHOR]

Background: A proportion of tuberculosis (TB) case contacts do not become infected, even when heavily exposed. We studied the innate immune responses of TB case contacts to understand their role in protection against infection with Mycobacterium tuberculosis, termed "early clearance."Methods: Indonesian household contacts of TB cases were tested for interferon-γ release assay (IGRA) conversion between baseline and 14 weeks post recruitment. Blood cell populations and ex vivo innate whole blood cytokine responses were measured at baseline and, in a subgroup, flow cytometry was performed at weeks 2 and 14. Immunological characteristics were measured for early clearers, defined as a persistently negative IGRA at 3 months, and converters, whose IGRA converted from negative to positive.Results: Among 1347 case contacts, 317 were early clearers and 116 were converters. Flow cytometry showed a resolving innate cellular response from 2 to 14 weeks in persistently IGRA-negative contacts but not converters. There were no differences in cytokine responses to mycobacterial stimuli, but compared to converters, persistently IGRA-negative contacts produced more proinflammatory cytokines following heterologous stimulation with Escherichia coli and Streptococcus pneumoniae.Conclusions: Early clearance of M. tuberculosis is associated with enhanced heterologous innate immune responses similar to those activated during induction of trained immunity. [ABSTRACT FROM AUTHOR]

Background: Damaging inflammation is thought to contribute to the high morbidity and mortality of tuberculous meningitis (TBM), but the link between inflammation and outcome remains unclear.Methods: We performed prospective clinical and routine laboratory analyses of a cohort of adult patients with TBM in Indonesia. We also examined the LTA4H promoter polymorphism, which predicted cerebrospinal fluid (CSF) leukocyte count and survival of Vietnamese patients with TBM. Patients were followed for >1 year.Results: We included 608 patients with TBM, of whom 67.1% had bacteriological confirmation of disease and 88.2% had severe (ie, grade II or III) disease. One-year mortality was 43.7% and strongly associated with decreased consciousness, fever, and focal neurological signs. Human immunodeficiency virus (HIV) infection, present in 15.3% of patients, was associated with higher mortality and different CSF characteristics, compared with absence of HIV infection. Among HIV-uninfected patients, mortality was associated with higher CSF neutrophil counts (hazard ratio [HR], 1.10 per 10% increase; 95% confidence interval [CI], 1.04-1.16), low CSF to blood glucose ratio (HR, 1.16 per 0.10 decrease; 95% CI, 1.04-1.30), CSF culture positivity (HR, 1.37; 95% CI, 1.02-1.84), and blood neutrophilia (HR, 1.06 per 109 neutrophils/L increase; 95% CI, 1.03-1.10). The LTA4H promoter polymorphism correlated with CSF mononuclear cell count but not with mortality (P = .915).Conclusions: A strong neutrophil response and fever may contribute to or be a result of (immuno)pathology in TBM. Aggressive fever control might improve outcome, and more-precise characterization of CSF leukocytes could guide possible host-directed therapeutic strategies in TBM. [ABSTRACT FROM AUTHOR]